And that is piling the pressure on Sam Allardyce and David Sullivan to find a cover defender ahead of then transfer window closing.
The player was sidelined from the 3-1 win over Crystal Palace last weekend because of suspension but the injury remained a closely guarded secret.
However the respected www.physioroom.com reportins the injury as being sustained on August 20 with no projected return date.
The central defender has withdrawn from the Wales squad to meet Andorra on September 9.
That means the long term injury will have to step up its efforts to bring in a central defender on loan before the transfer window closes.
And it also means that Winston Reid is set to be paired with James Tomkins at the heart of the weekend defence with Reece Burke again on the bench.